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Patented July 25, 1944 2,354,232

' BARBITURIC DERIVATIVES AND THEIR SALTS Lewis A. Walter, East Orange, N. J'., asslgnor to The Maltbie Chemical Company, Newark, N. 1., a corporation ot- New Jersey No Drawing. Application February 28, 1942, Serial No. 432,888

32 Claims. (Cl. 260-257) The present invention relates to certain new distillation and the residue dissolved in water. and useful 5.5 disubstituted barbituri-c acid de- The aqueous solution is then extracted with ether, rivatives, and their salts, having the formula: and the aqueous layer is separated and acidified,

yielding a precipitate of the desired barbituric RSCH CNH (I) acid derivative, which may then be filtered oi! 0 i and purified by crystallization from a suitable l solvent such as ethanol.

Suitable methods for re aration of alt f wherein R and R are hydrocarbon groups, either p p s S o the novel com oun saturated or unsaturated, and either the same p as are described hereafter or different, and each of which contains not more METHOD B than Six carbo a and wherein the Sum of A disubstituted cyano acetic ester represented the carbon atoms, in R and B does not exceed by the general formula: 10, it being understood that R has a carbon atom attached directly to the sulfur of the thiomethylene group and R has a carbon atom at- (2) tached directly to the carbon atom forming the H barbituric acid nucleus; and wherein X is a member selected from the class consisting of hywherein R and R have the si nificance stated drogen, alkali-metal, an equivalent of alkalineabove. and represents a er a y oup. is earth metal, ammonium, mono-alkyl ammonium, condensed w e i t e presence of sodium dialky1 ammonium, alkanol ammonium and an ethylate in absolute alcohol. The imino barequivalent of glkylene diammonium, biturate resulting from this reaction is then hy- These novel compounds, and their salts, when drolyzed t0 the corresponding barbituric acid tested pharmacologically, have been found to by fl x n with hydrochloric acid. The crude possess useful hypnotic or sedative properties, fl fi 801d Separating t from the acid mixmaking them valuable for various medical purture is then filtered off and recrystallized from a poses. They are, in general, white, crystalline So vent S ch as ethanol, to yield a pure barbituric solids. acid derivative.

The novel compounds according to my invenlts of the compounds may be prepared as tion may be prepared by the application of diihereafter described. ferent methods of synthesis, of which illustra- The following specific examples are illustrative tive ones, the best now known to me, will now of the novel compounds c nfl o y invenbe described. In general, however, I prefer, as tion, d 0! Suitable methQdS their P p at present advised, to employ Method A, in the tion:

preparation of a majority of the derivatives. In the following illustrative examples the term Y1 THE malonic ester" refers, unless otherwise indicated, ILLUSTRATIVE ODS OF S SIS to the diethyl ester of malonic acid:

Mnruon A EXAMPLE 1 This method comprises the condensation oi. a disubstituted malonic ester (such as may be pre- 5 n 5 ethylthgzethylene pared, for example, in accordance with application Serial No. 432,887, filed February 28, 1942) To 1.1 moles of metallic sodium, dissolved in with urea in the presence of sodium ethylate, in 500 cc. of absolute alcohol, 0.5 mole of ethylthman organic solvent such as, for example, abmethylene n-butyl malonic ester and 0.6 mole of solute alcohol, as illustrated by the following urea are added. This mixture is refluxed on equation: I steam bath for 12 hours, the alcohol is removed a 000R" a CO-N'H J, o (NHihCO c o 23 OH RSCHI/ oooa" RSCH: (JO-NH wherein R and R have the significance stated by Vacuum distillation and the residue is dissolved above, and R" is a lower alkyl group. When the in about 600 cc. of water. The aqueous oluti reaction is complete, the solvent is removed by is then extracted with ether and the aqueous;

layer is separated and acidified with acetic acid.

' The resulting precipitate of 5-n-butyl-5-ethylcmcms on, co-NH C CHsCHzCHnCHf C O-IQH EXAMPLE 2 5-ethyi-5-n-amylthiomethylene barbitunc acid To 1.1 moles of metallic sodium, dissolved in 500 cc. of absolute alcohol, 0.5 mole of amylthiomethylene ethyl malonic ester and 0.6 mole of urea are added. This mixture is refluxed on a steam bath for 12 hours, the alcohol is removed by vacuum distillation, and the residue is dissolved in about 600 cc. of water. The aqueous solution is then extracted with ether and the aqueous layer is separated and acidified with acetic acid. The resulting precipitate of 5-ethyl-5-namylthiomethylene barbituric acid is filtered oil and purified by crystallization'from alcohol. The derivative thus obtained has a melting point of approximately 107.5-108.5 C. (uncorrected), and is represented by the following formula:

EXAMPLE 3 5-ethyZ-5-allylthiomethylene barbituric acid To 1.1 moles of metallic sodium, dissolved in 500 cc. of absolute alcohol, 0.5 mole of allylthiomethylene ethyl malonic ester and 0.6 mole of urea are added. This mixture is refluxed on a steam bath for 12 hours, the alcohol is removed by vacuum distillation, and the residue is dissolved in about 600 cc. of water. The aqueous solution is then extracted with ether and the aqueous layer is separated and acidified with acetic acid. The resulting precipitate of 5-ethyl- 5-allylthiomethylene barbituric acid is filtered off and purified by crystallization from alcohol. The derivative thus obtained has a melting point of approximately 165-166 C. (uncorrected), and is represented by the following formula:

CHFCH-CHzS H, 0 0NH c I o (a) CHaCH: C O-NH Exsurm 4 S-ethyl-5-cycZohexylthi0meth1 Zene barbituric To 1.1 moles of metallic sodium, dissolved in 500 cc. of absolute alcohol, 0.5 mole cyclohexylthiomethylene ethyl malonic ester, and 0.6 mole of urea are added. This mixture is refluxed on a steam bath for 12 hours, the alcohol is removed by vacuum distillation and the residue is dissolved approximately 162 C. (uncorrected) and is repre. sented by the following formula:

OKs-CH CHPC Hg 0 (JO-B TE Exams: 5

5-ethyl-5-tertiary-butvlthlomethylenc barbituric acid filtered oil and purified by crystallization from alcohol. The derivative thus obtained has a melting point of approximately 186.5-187 C. (uncorrected), and is represented by the following formula:

oo-Nn (CHrhCBCHs CHrCH Exmu 6 5-n-butyi-5-n-butylthiomethulene barbituric acid To 1.1 moles of metallic sodium, dissolved in 500 cc. of absolute alcohol, 0.5 mole of n-butylthiomethylene n-butyl cyano acetic ester, having a boiling point of approximately -155 C. at about 1 mm. pressure, and 0.75 mole of urea are added. This mixture is refluxed on a steam bath for 12 hours, the alcohol is removed by vacuum distillation, and the residue is dissolved in about 600 cc. of water. The aqueous solution is extracted several times with ether, and the aqueous layer is separated and acidified with concentrated hydrochloric acid. When lust acid, an equal volume of concentrated hydrochloric acid is then added and the mixture is refluxed for 1 hour. on cooling, the crude barbituric acid separates and is then recrystallized from alcohol to yield 5-n-butyl-fi-nebutylthiomethylene barbituric acid, having a melting point of approximately HIS-108 C. (uncorrected), and is represented by the following formula:

I CHiCHgCHaCH| CO-NH valuable and useful properties as hypnotics or sedatives:

Barbituric acid RSCH: CO-NH- Ap roximate me] int, NH

n-Arnyllsoamyl l-methylbutyl yl 2-ethylbutyl In the foregoing examples, the melting points are approximate and uncorrectedtbut are those which I actually observe, according to a procedure believed to be reliable.

SALTS 01" THE NOVEL BARBITURIC ACID DERIVATIVES stirred with dry ether, gives the sodium salt in amorphous form.

Other alkali-metal salts may also be derived by a similar procedure.

The sodium salts of my novel barbituric acid derivatives have been found to be readily soluble in water, and their aqueous solutions are alkaline in reaction. When administered orally or hypodermically in proper dosage they are good and useful hypnotics or sedatives, and range in duration of action from long to ultra-short acting.

Calcium salts may be prepared by treating an absolute alcohol solution of the sodium salt with the metathetical amount of alcoholic calcium chloride, filtering oi! the precipitated sodium chloride and concentrating the alcoholic solution to yield the calcium salt.

The ammonium, alkyl and alkanol ammonium salts may be prepared by dissolving the corresponding barbituric acid in an excess of ammonia or amine and subsequently removing the excess quantity of base.

In the following claims it is to be understood that barbituric acid derivatlve"-and similarexpressions, includes, also, the salts of such derivatives, such as, for example, the salts described above.

The examples given above, and illustrative processes for their production, include the best embodiments army present invention now known to me: but it is to be understood that the invention is not necessarily or specifically limited thereto and may, under proper conditions, have other embodiments, produced in other ways, without departure from the spirit of the invention, and within the scope of the following claims.

What is claimed is:

1. As a new and useful composition of matter, a 5,5 disubstituted barbituric acid derivative having the'iormula I RS on, co-nn c R/ o 0l IX wherein R. and R are hydrocarbon groups, each of which contains not more than six carbon atoms, and wherein the sum of the carbon atoms in R and R does not exceed 10, R. has a carbon atom attached directly to the sulfur of the thicmethylene group, and R has a carbon atom attached directly to the carbon atom forming the barbituric acid nucleus; and wherein X is a member elected from the class consisting of hydrogen, alkali-metal, an equivalent of alkalineearth metal, ammonium, mono-alkyl ammonium, dialkyl ammonium, alkanol ammonium, and an equivalent of alkylene diammonium.

2. A composition of matter according to claim 1 in which at least one 01' the R and R groups is a primary hydrocarbon group.

3. A composition of matter according to claim 1 in which X represents hydrogen.

4. A composition of matter according to claim 1 in which R and R are both primary hydrocarbon groups.

5. A composition of matter according to claim 1 in which R and R are both primary hydrocarbon groups and X represents hydrogen.

6. A composition or matter according to claim 1 in which R is a secondary hydrocarbon group and R is a primary hydrocarbon group.

' '7. A composition of matter according to claim 1 in which R is a secondary hydrocarbon group, R is a primary hydrocarbon group and X represents hydrogen.

8. A composition or matter according to claim 1 in which R is a primary hydrocarbon group and 'in which X represents hydrogen.

12. A composition of matter according to claim 1 in which R is a primary hydrocarbon group and R is an ethyl group.

13. A composition or matter according to claim 1 in whichR is a primary hydrocarbon group, R is an ethyl group and x represents hydrogen.

14. A composition or matter according to claim 1 in which R is a primary hydrocarbon group containing 5 carbon atoms and R is a primary hydrocarbon group.

15. A composition of matter according to claim 1 in which R is a primary hydrocarbon group containing 5 carbon atoms, R'\ is a primary hydrocarbon group and x represents hydrogen.

16. A composition of matter according to claim 1 in which R is a'primary hydrocarbon group containing 5 carbon atoms and R is an ethyl group.

17. A composition of matter according to claim 1 in which R is a primary hydrocarbon group containing 5 carbon atoms, R is an ethyl group and X represents hydrogen.

18. A composition 01' matter according to claim 1 in which R is an n-amyl group and R is a primary hydrocarbon group.

19. A composition of matter according to claim 1 in which R is an n-amyl group, R is a primary hydrocarbon group and X represents hydrogen.

20. A composition 01 matter according to claim 1 in which R is an n-amyl group and R is an ethyl group.

21. A composition of matter according to claim 1 in which R is an n-amyl group, R is an ethyl group and X represents hydrogen.

22. A composition oi matter according to claim I 1 in which R is an ethyl group and R is a secondary hydrocarbon group.

23. A composition of matter according to claim 1 in which R is an ethyl group, R is a secondary hydrocarbon group and x represents hydrogen. 24. A composition of matter according to claim 1 in which R is a primary hydrocarbon group and R is a secondary hydrocarbon group containing 5 carbon atoms.

25. A composition of matter according to claim 1 in which R is a primary hydrocarbon group. R is a secondary hydrocarbon group containing 5 carbon atoms and X represents hydrogen 26. A composition of matter according to claim 1 in which R is a primary hydrocarbon group and R is a l-methyl-butyl group.

27. A composition of matter according to claim 1 in which R is a primary hydrocarbon group, R is a l-methyl-butyl group and x represents hydrogen.

28. A composition of matter according to claim 1 in which R is an ethyl group and R is a 1- methyl-butyl group.

29. A composition of matter according to claim 1 in which R is an ethyl group, R is a l-methylbutyl group and X represents hydrogen.

30. 5-secondary-butyl 5 ethylthiomethylene barbituric acid.

31. 5-ethy1-5-isoamylthiomethylene barbituric acid.

32. Th method of producing a 5,5 disubstituted barbituric acid derivative according to claim 1 which comprises condensing the corresponding 5,5 disubstituted malonic ester with urea in the presence or sodium ethylate in an organic solvent.

. LEWIS A. WALTER. 

